1977年4月500毫巴环流指数、环流型、环流特征量资料

341977年4月500毫巴环流指数、环流型、环流特征量资料~~     

亚洲500毫巴环流指数的若干特徵

本文参考計算环流指数的方法,計算了亚洲地区(60—150°E)500毫巴多年月平均图上的緯向和經向环流指数,研究了它們随緯度变化的性貭和季节变化的特征,并与全北半球的环流指数相比較.在詳細地計算了亚洲中高緯度地区(60—150°E,45—65°N)逐候(或自然天气周期)的环流指数的基础上,討論了月平均环流指数的性貭、分布情况和季节变化的特征,統計分析了它們的某些天气气候規律。最后,分析了亚洲环流指数的多年变化及与我国天气的关系,指出它們具有长周期的振动,并与太阳活动有一定的关联。     

500毫巴环流指数、环流型及环流特征量

1.500毫巴月平均环流指数分亚欧地区(45—65°N、0—150°E)和亚洲地区(45—65°N、60—150°E),其计算公式, 其中φ_1、φ_2表示计算纬向环流指数Iz的纬度范围,Z_(1i)、Z_(2i)分别是在φ_1、φ_2两纬圈上第i点的500毫巴高度读数,L为分别在φ_1、φ_2纬圈上均匀取点进行高度读数的点数。计算经向环流指数Im时,先将所考虑范围分成n个小区,在m个纬圈上分别读取经度间距为Δλ的相邻两点间高度差ΔZi,然后进行计算(详见中央气象科学研究所《论文汇集》1965年9月)。这里所附的月平均环流指数值是根据上式计算的逐候平均环流指数,     

1996年6月500hPa环流指数、环流特征量资料

１９９６年６月５００ｈＰａ环流指数、环流特征量资料国家气候中心气候预测室环流指数西太平洋副热带高压东亚槽极涡月平均候平均１２３４５６面积指数强度指数西伸脊点脊线位置北界位置平均位置平均强度中心位置经度纬度强度亚欧ＩＺ０．８６１．００１．０２０．８８０...     

1995年12月500hPa环流指数、环流特征量资料

１９９５年１２月５００ｈＰａ环流指数、环流特征量资料国家气候中。Ｃ气候预测室１９９５年１２月亚洲地区逐日５００ｈＰａ西风环流指数中央气象台中期预报科１９９５年１２月５００ｈＰａ平均高度、涡度距平的球函数展开系数、振幅、位相国灾与候中心1995年12月500hPa...     

2006年8月500hPa环流指数、环流特征量资料

环流指数西太平洋副热带高压东亚槽极涡平均月候平均123456积指数面度指数强伸脊点西线位置脊界位置北均位置平均强度平经中度心位纬置度强度亚欧地区IZIM0.970.351.010.390.910.220.700.401.160.351.110.270.910.45亚洲地区IZIM1.150.351.240.421.110.280.900.301.280.331.410.320.970.4530311002933999999105E85N272006年8月500hPa环流指数、环流特征量资料$国家气候中心气候预测室~~…     

2006年11月500hPa环流指数、环流特征量资料

环流指数西太平洋副热带高压东亚槽极涡平均月候平均123456积指数面度指数强伸脊点西线位置脊界位置北均位置平均强度平经中度心位纬置度强度亚欧地区IzI m1.300.841.580.971.381.141.370.731.190.791.180.631.100.79亚洲地区IzI m1.130.771.670.650.931.241.070.931.170.601.120.470.830.741929105172112815580°W80°N42006年11月500hPa环流指数、环流特征量资料$国家气候中心气候系统诊断预测室~~…     

1977年2—3月500毫巴环流指数、环流型、环流特征量资料

~~1977年2—3月500毫巴环流指数、环流型、环流特征量资料~~     

2007年2月500hPa环流指数、环流特征量资料

环流指数西太平洋副热带高压东亚槽极涡平均月候平均123456积指数面度指数强伸脊点西线位置脊界位置北均位置平均强度平经中度心位纬置度强度亚欧地区IzI m1.670.501.890.681.630.391.450.321.630.511.630.571.800.51亚洲地区IzI m1.870.482.150.581.740.471.500.401.790.462.060.441.970.541420110121414397105°E70°N-12007年2月500hPa环流指数、环流特征量资料$国家气候中心气候系统诊断预测室~~…     

2006年3月500hPa环流指数、环流特征量资料

国家气候中心气候预测室环流指数西太平洋副热带高压东亚槽极涡月平均候平均123456中心位置经度纬度强度亚欧地区IZ IM1.390.631.470.521.400.870.880.681.410.581.410.681.750.43亚洲地区IZ IM1.450.641.500.531.370.751.240.781.770.561.080.771.710.46671251418133116130°E60°N112006年3月500hPa环流指数、环流特征量资料$国家气候中心气候预测室~~     

武汉年平均气温的灰色预测

本文利用武汉80年的年平均气温资料,在对气温时间序列进行谱分析的基础上,利用灰色系统中的二阶动态预测模型——GM(2,1),对武汉气温未来的变化趋势进行了分析。得出武汉仍将处于偏冷期,预计90年代初开始转为回升,下世纪第10年后出现明显偏暖。     

Circulation factors affecting precipitation over Bulgaria

The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, showing west-east or south-north transport of air masses over Bulgaria and four teleconnection indices (patterns)—North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian. Omega values at 700-hPa level show vertical motions in the atmosphere. Annual precipitation trends are mixed and not statistically significant. A significant decrease of precipitation in Bulgaria is observed in November due to the strengthening of the eastward transport of air masses (strengthening of EA teleconnection pattern) and anticyclonal weather (increase of descending motions in the atmosphere). There is also a precipitation decrease in May and June due to the growing influence of the Azores High. An increase of precipitation happens in September. All this leads to a redistribution of annual precipitation course, but annual precipitation amounts remain the same. However, this redistribution has a negative impact on agriculture and winter ski tourism. Zonal circulation has a larger influence on precipitation in Bulgaria compared to meridional. Eastward transport throughout the year leads to lower than the normal precipitation, and vice versa. With regard to the four teleconnection patterns, winter precipitation in Bulgaria is determined mainly by EA/WR teleconnection pattern, spring and autumn by EA teleconnection pattern, and summer by SCAND teleconnection pattern.     

Linkage Between the Northeast Mongolian Precipitation and the Northern Hemisphere Zonal Circulation

The long-term relationship between the tree-ring-reconstructed annual precipitation in northeastern Mongolia (PRM) and the Northern Hemisphere Zonal Circulation (NHZC)§defined as the normalized zonal mean sea-level pressure at 60N in May-June-July, is examined in this study. A significant correlation coefficient (0.31) was found between the NHZC indices and PRM based on the dataset for the period of 1872–1995. The mechanisms responsible for the relationship are discussed through analyses of the atmospheric general circulation variability associated with NHZC. It follows that NHZC-related atmospheric circulation variability provides an anomalous southeast flow from the ocean to Northeast Mongolia (northwest flow from Northeast Mongolia to the ocean) in the middle and low troposphere in positive (negative) phase of NHZC, resulting in more (less) water vapor transport to the target region and more (less) precipitation in Northeast Mongolia.     

Circulation indices over the Mediterranean and Europe and their relationship with rainfall conditions across the Mediterranean

Summary Circulation types were identified by means of zonal and meridional indices calculated separately over ten different regions of 20° × 20° over the Mediterranean and Europe. Seasonal and annual rainfall totals in four stations Lisbon, Luqa (Malta), Athens and Jerusalem, were compared with circulation types for the period 1873–1991. Correlation coefficients of circulation indices with precipitation, for each station in each season were calculated and mapped.An oscillation in the meridional index during the winter and the spring, between the western and eastern Mediterranean, was detected.Time series analysis of the circulation indices demonstrates a significant reduction in zonality and an increase in meridionality mainly in spring and in summer, over most of the study area.With 9 Figures     

热带环流强度变化与我国夏季降水异常的关系

该文用850 hPa和200 hPa纬向风距平差定义南海热带季风、沃克环流及热带环流强度指数,并讨论它们的天气气候学意义。指出由南海热带季风指数和沃克环流指数之差表征的热带环流强度指数与我国夏季降水,尤其是与长江流域降水有密切的关系;通过热带环流强度指数与冬、春、夏季500 hPa高度场、SLP、SST、OLR的相关分析,揭示用热带环流强度指数表征的热带环流异常影响我国夏季降水的可能途径。热带环流强度指数的季节变化规律及其与前期环境场的相关关系,对夏季雨带位置的预报有一定的参考价值。     

Twentieth century Walker Circulation change: data analysis and model experiments

Recent studies indicate a weakening of the Walker Circulation during the twentieth century. Here, we present evidence from an atmospheric general circulation model (AGCM) forced by the history of observed sea surface temperature (SST) that the Walker Circulation may have intensified rather than weakened. Observed Equatorial Indo-Pacific Sector SST since 1870 exhibited a zonally asymmetric evolution: While the eastern part of the Equatorial Pacific showed only a weak warming, or even cooling in one SST dataset, the western part and the Equatorial Indian Ocean exhibited a rather strong warming. This has resulted in an increase of the SST gradient between the Maritime Continent and the eastern part of the Equatorial Pacific, one driving force of the Walker Circulation. The ensemble experiments with the AGCM, with and without time-varying external forcing, suggest that the enhancement of the SST gradient drove an anomalous atmospheric circulation, with an enhancement of both Walker and Hadley Circulation. Anomalously strong precipitation is simulated over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. Some sensitivity to the forcing SST, however, is noticed. The analysis of twentieth century integrations with global climate models driven with observed radiative forcing obtained from the Coupled Model Intercomparison Project (CMIP) database support the link between the SST gradient and Walker Circulation strength. Furthermore, control integrations with the CMIP models indicate the existence of strong internal variability on centennial timescales. The results suggest that a radiatively forced signal in the Walker Circulation during the twentieth century may have been too weak to be detectable.     

Application of blocking diagnosis methods to General Circulation Models. Part I: a novel detection scheme

This paper aims to provide a new blocking definition with applicability to observations and model simulations. An updated review of previous blocking detection indices is provided and some of their implications and caveats discussed. A novel blocking index is proposed by reconciling two traditional approaches based on anomaly and absolute flows. Blocks are considered from a complementary perspective as a signature in the anomalous height field capable of reversing the meridional jet-based height gradient in the total flow. The method succeeds in identifying 2-D persistent anomalies associated to a weather regime in the total flow with blockage of the westerlies. The new index accounts for the duration, intensity, extension, propagation, and spatial structure of a blocking event. In spite of its increased complexity, the detection efficiency of the method is improved without hampering the computational time. Furthermore, some misleading identification problems and artificial assumptions resulting from previous single blocking indices are avoided with the new approach. The characteristics of blocking for 40 years of reanalysis (1950–1989) over the Northern Hemisphere are described from the perspective of the new definition and compared to those resulting from two standard blocking indices and different critical thresholds. As compared to single approaches, the novel index shows a better agreement with reported proxies of blocking activity, namely climatological regions of simultaneous wave amplification and maximum band-pass filtered height standard deviation. An additional asset of the method is its adaptability to different data sets. As critical thresholds are specific of the data set employed, the method is useful for observations and model simulations of different resolutions, temporal lengths and time variant basic states, optimizing its value as a tool for model validation. Special attention has been paid on the devise of an objective scheme easily applicable to General Circulation Models where observational thresholds may be unsuitable due to the presence of model bias. Part II of this study deals with a specific implementation of this novel method to simulations of the ECHO-G global climate model.     

季风环流对黑龙江省气候的影响分析

本文从季风环流对黑龙江省气候在冬季、夏季温度差异;季风环流对大气降水时间和空间分布的影响;季风环流对春秋两季的影响等方面进行了详细的分析。结果表明,黑龙江省的冬夏季因受强大的蒙古高压前缘冷空气和季风的影响温差悬殊;受季风的影响降水量主要集中于夏季,降水空间分布则是从自东向西逐渐递减的特点。     

一个耦合气候模式中的副极地涡旋指数与北大西洋经向翻转流

The subpolar gyre index (SPG), derived from the analysis of sea surface height (SSH), is proposed to be a potential indicator for the North Atlantic Meridional Overturning Circulation (AMOC) based on observation as well as the Ocean General Circulation Model (OGCM). We investigated the correspondence between the SPG and the AMOC in a coupled climate model. Our results confirm that the SPG can be used as an early indicator for the AMOC in the subtropical North Atlantic. Changes in the SPG are closely related to variations in the air-sea heat exchange in the Labrador Sea, and variations in deep water formation and southward dense water transport with the deep western boundary current (DWBC) in the North Atlantic. Citation: Gao, Y. Q., and L. Yu, 2008: Subpolar gyre index and the North Atlantic meridional overturning circulation in a coupled climate model, Atmos. Oceanic Sci. Lett., 1, 29-32     

Circulation over Bulgaria and its connection with NAO indices and Sea Surface Temperatures

Trends in atmospheric pressure, circulation and some relationships between North Atlantic Oscillation (NAO) indices, sea surface temperatures, and atmospheric circulation over Bulgaria are discussed in this article. Data for measured atmospheric pressure at stations Burgas, Pleven, and Sandanski are used. Information about atmospheric circulation over Bulgaria was obtained using sea level pressure and 700 hPa Omega (vertical velocity) reanalysis daily data for grid cells covering the territory of Bulgaria for the period 1948–2010. Zonal and meridional indices for Bulgaria were also calculated based on the data for sea level pressure. NAO index calculated by NOAA and NCAR is correlated with atmospheric pressure and circulation. A total of 12 areas in three major water basins influencing Bulgarian climate—North Atlantic, Mediterranean, and Black Seas—were studied. Main methods employed in the article are statistical—trend analysis, multiple linear regression, correlation, nonparametric tests, etc. There is no change in the mean values of atmospheric pressure over Bulgaria. Circulation over Bulgaria during the research period increases its anticyclonal patterns mainly due to the decrease of the number of cyclones. Dynamics in zonal and meridional indices for Bulgaria result in an increase of the northwest transport in the winter and an increase of the northeast transport in the summer. Cyclones over Bulgaria determine the values of atmospheric pressure. Influence of the NAO on atmospheric pressure and circulation is stronger in winter. Atmospheric processes, expressed by the number of cyclones and anticyclones, are most active in spring. Current trends are towards increasing of sea surface temperatures (SSTs) at all investigated places. Temporally, the effect of SSTs on the number of cyclones, anticyclones, zonal and meridional indices for Bulgaria during the different seasons comes with a delay of 1 to 3 months. Constructed multiple linear regression (MLR) models with predictors SSTs adequately describe the atmospheric circulation over Bulgaria. There is a clear pattern of SSTs distribution, which leads to a higher number of cyclones over Bulgaria in winter—lower than normal temperatures in the Aegean Sea and higher than normal in the Black Sea. A decrease in the difference of temperatures between the Gulf Stream and western colder parts leads to higher values of winter zonal transport over Bulgaria. Higher than normal temperatures in Black Sea lead to a higher number of cyclones in spring. Higher difference in temperatures of the North Atlantic leads to a stronger cyclogenesis and enhanced zonal transport, which affects autumn circulation over Bulgaria.